Optimising bess sizing for energy-intensive industries: self-consumption vs. market sales in Italy

To meet Europe’s 2050 climate neutrality target, energy-intensive companies must cut Carbon Dioxide CO2 emissions. Investing in Photovoltaics (PV), supported by Battery Energy Storage Systems (BESSs), is key to managing PVs’ variability and reducing grid reliance. This study analyses two BESS management strategies, coupled with an 7.5 MW-PV system, for an energy-intensive company in Italy, namely: i) maximising self-consumption to lower emissions and costs and ii) selling excess energy in the Day-Ahead Market (DAM) and Capacity Market (CM) for the economic revenue R and grid support. Results show that the optimal BESS size for energy self-consumption is 10.7 MWh with an 80% Depth of Discharge (DoD), increasing to 11.6 MWh with a 90% DoD. On the other hand, the optimal BESS size for market participation equals 10.4 MWh with a 90% DoD, where 10% are devolved to the CM. As a result, lower market premiums make this approach less viable, and the findings highlight the trade-offs between financial returns and emission reduction.